OAK BROOK ESTATES
NPDES ID: IN0031844
E — SNC: Effluent violation (monthly average limit)
The facility discharged more of a pollutant than its permit allows, based on a monthly average.
This quarter: 3 effluent violations.
Violations
May 31, 2026
Nitrogen, ammonia total [as N]
73% over limit
Discharged 3.11 mg/L against a permitted limit of 1.8 mg/L (MX WK AV)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
54% over limit
Discharged 1.849 mg/L against a permitted limit of 1.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
April 30, 2026
Nitrogen, ammonia total [as N]
23% over limit
Discharged 3.32 mg/L against a permitted limit of 2.7 mg/L (MX WK AV)
DMR, Limited - Numeric Violation
March 31, 2026
Nitrogen, ammonia total [as N]
17% over limit
Discharged 0.583844 kg/d against a permitted limit of 0.4994 kg/d (MO AVG)
DMR, Limited - Numeric Violation
Oxygen, dissolved [DO]
57% over limit
Discharged 2.13 mg/L against a permitted limit of 5 mg/L (DLYAVMIN)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
76% over limit
Discharged 1.28027999 kg/d against a permitted limit of 0.72639999 kg/d (MX WK AV)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
720% over limit
Discharged 22.13 mg/L against a permitted limit of 2.7 mg/L (MX WK AV)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
431% over limit
Discharged 9.557 mg/L against a permitted limit of 1.8 mg/L (MO AVG)
DMR, Limited - Numeric Violation
February 28, 2026
Oxygen, dissolved [DO]
29% over limit
Discharged 3.57 mg/L against a permitted limit of 5 mg/L (DLYAVMIN)
DMR, Limited - Numeric Violation
BOD, carbonaceous [5 day, 20 C]
85% over limit
Discharged 74.17 mg/L against a permitted limit of 40 mg/L (MX WK AV)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
20% over limit
Discharged 0.87167999 kg/d against a permitted limit of 0.72639999 kg/d (MX WK AV)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
154% over limit
Discharged 4.568 mg/L against a permitted limit of 1.8 mg/L (MO AVG)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
524% over limit
Discharged 16.85 mg/L against a permitted limit of 2.7 mg/L (MX WK AV)
DMR, Limited - Numeric Violation
November 30, 2025
Nitrogen, ammonia total [as N]
43% over limit
Discharged 2.58 mg/L against a permitted limit of 1.8 mg/L (MX WK AV)
DMR, Limited - Numeric Violation
January 31, 2025
Nitrogen, ammonia total [as N]
24% over limit
Discharged 3.36 mg/L against a permitted limit of 2.7 mg/L (MX WK AV)
DMR, Limited - Numeric Violation
December 31, 2024
Nitrogen, ammonia total [as N]
65% over limit
Discharged 4.46 mg/L against a permitted limit of 2.7 mg/L (MX WK AV)
DMR, Limited - Numeric Violation
November 30, 2024
Nitrogen, ammonia total [as N]
119% over limit
Discharged 3.95 mg/L against a permitted limit of 1.8 mg/L (MX WK AV)
DMR, Limited - Numeric Violation
Nitrogen, ammonia total [as N]
18% over limit
Discharged 1.415 mg/L against a permitted limit of 1.2 mg/L (MO AVG)
DMR, Limited - Numeric Violation
First flagged
April 14, 2026 (3 months ago)
Last confirmed
August 1, 2026 (4 days ago)